JSP Tag Libraries

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send-mail scriptlet. This also means that when developing new projects, you can take advantage of tested assets developed for past projects.

This reusability provides huge savings in development and testing time: one more reason to use tags and one more consideration when developing tags. Always develop your tags with reusability in mind.

15.1.3    Maintaining tags

Once you have finished developing your application, you need to maintain it. Roughly speaking, application maintenance includes fixing business logic bugs and fixing/ updating the presentation. (The latter will be your major maintenance activity.)

As long as you are not using scriptlets, fixing the presentation does not require any Java skills. If you use scriptlets, however, any change to the presentation may require a review by a Java programmer and maybe even a testing session. Using tags frees you from this burden.

On the business logic front, when you use tags instead of scriptlets, you needn’t check out the JSP files. Fixing a bug becomes an issue of stepping through the Java code; all JSP files can be left untouched.

Clearly, in addition to reusability and improved productivity for the nonprogrammer, using tags also reduces your maintenance costs.

15.1.4    Tags and application performance

Many die-hard scriptlet coders complain to us that tags are slower than scriptlets and using them renders JSP performance unacceptable. These are the same people who insist, “Real programmers code in assembly.” In reality, the performance impact (if any) of using tags is overshadowed by the savings in development time and by pared down maintenance.

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